Perirhinal Cortex Contributes to Accuracy in Recognition Memory and Perceptual Discriminations

Abstract

The prevailing view of the medial temporal lobe (MTL) holds that its structures are dedicated to long-term declarative memory. Recent evidence challenges this position, suggesting that perirhinal cortex (PRc) in the MTL may also play a role in perceptual discriminations of stimuli with substantial visual feature overlap. Relevant neuropsychological findings in humans have been inconclusive, likely because studies have relied on patients with large and variable MTL lesions. Here, we conducted a functional magnetic resonance imaging study in healthy individuals to determine whether PRc shows a performance-related involvement in perceptual oddball judgments that is comparable to its established role in recognition memory. Morphed faces were selected as stimuli because of their large degree of feature overlap. All trials involved presentation of displays with three faces. The perceptual oddball task required identification of the face least similar to the other display members. The memory task involved forced-choice recognition of a previously studied face. When levels of behavioral performance were matched, we observed comparable levels of activation in right PRc for both tasks. Moreover, right PRc activity differentiated between accurate and inaccurate trials in both tasks. Together these results indicate that declarative memory demands are not a prerequisite for a performance-related engagement of PRc and that the introduction of such declarative memory demands in an otherwise closely matched perceptual task does not necessarily lead to an increase in PRc involvement. As such our findings show that declarative memory and perception are not as clearly separable at the level of MTL functioning as traditionally thought.

Reducing perceptual interference improves visual discrimination in mild cognitive impairment: Implications for a model of perirhinal cortex function

“…Thus, it is not surprising that PRC function would be compromised. Consistent with this, the profile of performance in both the MCI patients and those at risk for MCI is remarkably consistent with findings from research that allows more precise localization of the PRC: (1) animal studies that have demonstrated object discrimination deficits and interference effects after precise, localized PRC lesions (Buckley et al, 2001;Bussey et al, , 2003Bartko et al, 2010;McTighe et al, 2010), and (2) functional neuroimaging revealing PRC activity in healthy participants during the discrimination task reported here and other tasks taxing complex object perception (Devlin and Price, 2007;Lee et al, 2008;O'Neil et al, 2009;Barense et al, 2010aBarense et al, , 2011a. In addition, based on the intact performance of amnesic patients with focal hippocampal damage ; Supporting Information Fig.…”

“…According to this theory, the primary function of the MTL is in memory and not in other aspects of cognition, such as object perception (Clark et al, 2011;Kim et al, 2011;Squire and Wixted, 2011). However, recent reports have challenged this prevailing view that the mechanisms underlying memory and perception are anatomically segregated, suggesting instead that the MTL-in particular the perirhinal cortex (PRC)-is not only important for memory but also essential for certain forms of perception (e.g., Buckley et al, 2001;Lee et al, 2005a;Bartko et al, 2007b;O'Neil et al, 2009;Barense et al, 2010b;Lee and Rudebeck, 2010;Barense et al, 2011a,b;Murray and Wise, 2012). These findings have led to a representational-hierarchical account of PRC function ( Fig.…”

A Role for Perirhinal Cortex in Memory for Novel Object–Context Associations

“…Evidence supporting this distinction includes findings that activity in the PrC at the time of encoding predicts successful item memory, while activity in the HC (and sometimes PhC) correlates with accurate context judgments (Cansino et al, 2002;Davachi et al, 2003;Ranganath et al, 2004;Yonelinas et al, 2005;Kensinger and Schacter, 2006). This view has been challenged by functional magnetic resonance imaging (fMRI) findings in which PrC has been implicated in memory processes beyond item memory, including encoding of object-context associations (Awipi and Davachi, 2008;Davachi, 2008, 2010;O'Neil et al, 2009;Duarte et al, 2011;Staresina et al, 2011). For example, Staresina et al (2011) reported that activity in the HC during memory encoding predicted subsequent memory for associations involving scenes as well as objects, while activity in the PrC did so only for objects.…”

Neural microgenesis of personally familiar face recognition

“…Although the hippocampus and perirhinal cortex are traditionally considered to mediate explicit recollection based on episodic memory and diffuse feelings of familiarity, recent studies indicate that these regions are also involved in visual discrimination (26,(29)(30)(31)(32)(33). Furthermore, various studies have also reported anterior ventral temporal activation for familiar (famous) face recognition (11), discrimination of familiar from unfamiliar faces (34)(35)(36)(37)(38) and face naming (39).…”